1. Field of the Invention
The present invention relates to an electrolytic ion-water production apparatus in which an electrolytic cell is provided to electrolyze tap water supplied from a tap water supply conduit through a water purifier for eliminating residual chlorine thereby to produce acid-ion water and alkaline-ion water.
2. Description of Prior Art
Disclosed in Japanese Patent Laid-open Publication No. 7(1995)-16570 is an electrolytic ion-water production apparatus of this kind in which an electrolytic cell is continuously supplied with tap water purified by a water purifying cartridge in connection to a tap water supply conduit and is applied with DC voltage at electrodes provided therein to electrolyze the purified tap water for producing alkaline-ion water and acid-ion water. The electrolytic ion-water production apparatus includes changeover means for selectively connecting the tap water supply conduit to either the water purifying cartridge or a bypass passage of the cartridge and control means for stopping power supply to the electrodes in the electrolytic cell when the changeover means is activated to connect the tap water supply conduit to the bypass passage of the water purifying cartridge.
In Japanese Utility Model Laid-open Publication No. 5(1993)-49092, there is disclosed changeover means disposed between each start end of a water supply portion and a water supply passage and each terminal end of a water circulation passage and a one-way bypass passage to alternately supply fresh tap water from the water supply portion to the water supply passage and the water circulation passage in accordance with operation of the changeover means. In this system, even if the tap water is remained in the water supply passage or the circulation passage, the remained water will be discharged by reverse flaw of the fresh tap water from the water supply portion so that propagation of microbes in the water supply passage and the circulation passage is prevented by germicidal function of chlorine contained in the fresh tap water.
In the ion-water production apparatus described above, fresh tap water is retained in an introduction passage of alkaline-ion water in a non-used condition of the apparatus so that propagation of microbes is prevented by residual chlorine in the fresh tap water. It has been proposed to changeover the introduction passages of alkaline-ion water and acid-ion water discharged from the electrolytic cell thereby to supply the acid-ion water into the introduction passage of alkaline-ion water for prevention of propagation of microbes.
The fresh tap water is, however, approximately neutral (in an extent of pH 5.8˜pH8.6 defined under the tap water law). Accordingly, the residual chlorine contained in the tap water is in the form of hypochlorous acid (HOCl) which is superior in quick effect of sterilization but inferior in durability of the sterilization effect. The concentration of hypochlorous acid is, however, decreased in accordance with lapse of a time. As the pH of residual chlorine contained in the acid-ion water is low, the residual chlorine is in form of hypochlorous acid and chlorine (Cl2) which are superior in sterilization effect but inferior in durability. Additionally, as chlorine gas soaks into the conduit material of the introduction passage of alkaline-ion water, foul smell of chlorine is mixed with alkaline-ion water produced at the next use of the apparatus.